Copper compositions and method for making the same



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4 v in? Unite' States Patent O ce COPPER COMPOSITIONS AND METHOD FOR MAKING THE SAME John W. Manquen, Berkley, and Henry Brown, Huntington Woods, Mich., assignors to The Udylite Research Corporation, Detroit, Mich., a corporation of Michigan No Drawing. Filed Dec. 4, 1958, Ser. No. 778,067

18 Claims. (Cl. 204-52) This invention relates to the electrodeposition of copper from aqueous alkaline cyanide solutions. More particularly, this invention relates to the use of certain new organic addition agents for cyanide copper plating baths, and especially to the use of a new combination of addi tion agents to achieve bright, very fine-grained, ductile copper electrodeposits over a very wide range of cathode current densities.

It has been found that the addition of certain acetylcnic ether nitriles (illustrated in Table I) to aqueous alkaline copper cyanide plating baths as the sole brightening agent increases the luster of the copper electrodeposits. When these compounds of Table I are used in conjunction with water soluble salts (e.g. Na or K salts) of methylene bis-(naphthalene sulfonic acids) as exaem plified by the formula I C 2 -----CH2 :Na 01' P,etc., l salts l l S0313 Where n is a whole number, and especially the methylene bis-(alpha naphthalene sulfonic acids), in an amount of 0.1 to 10 grams/liter an enhanced brightness occurs in the medium current density range plate down to the very low current density range plate.

TABLE I Useful Concert tration Range, grams/liter.

(1) HO-CHg-CEC-OIHOCzH-TCEN (l-Hydroxy-4 0.021.0(0.1-.0.3

(beta cyanoethoxy) butyne-Z). average) (2) NEC-C HiOCH CEC CHZOC H CEN (1,4- ;021.0 (0.2 Dl-(beta cyanoethoxy) bntynoZ). average).

dioxide directly in the bath. When tellurium is present in the bath in a concentration of about 00002-0006 grams/liter, preferably about 2 mg./liter in conjunction with a compound from Table I or 2-butyne-l,4-diol at a concentration of about 0.l-0.3 grams/liter, and methylene bis- (naphthalene sulfonic acids) at a concentra- A sium.

2,970,951 Patented Feb. 7, 1961 The copper cyanide baths can be made up of copper cyanide and an alkali metal cyanide with or without the addition of an alkali metal hydroxide or carbonate, and with or without the addition of tartrates, glycolates, or gluconates, citrates, malates or other similar organic acids or their salts such as the sodium, potassium or ammonium salts. In general, the preferred baths contain salts of these organic acids. Preferably the baths should contain both sodium and potassium ions, through the alkali metal ions may be exclusively sodium or potas- Satisfactory results are obtained when the copper cyanide varies between about 3 to about 12 ounces per gallon, the alkali metal cyanide varies between about 4.5 to about ounces per gallon, and the alkali metal hydroxide varies between about 0.5 and about 4 ounces per gallonl 'l'he cop-per cyanide baths are preferred to tion of about 3 grams/liter, with the conjunctive use of f these threetypes of brighteners, the tendency for formation of cloudy plate at the high current density areas isminimized and the brightness of the plate is greatly enhanced "uniformly fromthe highest current density ranges down to the lowest current densityranges. Moreover the presence of tellurium greatly decreases the tendency of the plate to stain, particularly from humidity and fingerprints. .1

be operated warm, with optimum results at temperatures of 50 C.'*95 C., though cooler or warmer baths may be used with excellent results. It is preferred to use the baths of composition similar to'the examples given below, operated at the maximum current densities which can be used under the given conditions of temperature and agitation. Under the usual conditions of commercial operation, cathode current densities of 10-60 ampcres per square foot are used with the normal cathode rod type agitation, or solution agitation; On articles of simple shape, current densities of amps/sq. ft. can be used when vigorous agitation is used. The following three examples are intended to illustrate typical copper baths which produce copper plate of good luster and color but not of the highest brightness.

Example I Ounces Grams/liter gal.

6.0 45. 9. 7 72.75. 2.0 15. 6.0 45. 1-hydroxy4-(bota cyanoethoxy) butyne-2 0.021.0 (average (Compound I, Table I). 0.1-0.3).

Example ll Oz. /ge1 Grams/liter Copper cyanide 4. 0 30. Sodium cyanide..-" 5.0 37.5. Sodium hydroxid 2. 5 18.75. Rochelle salts f. 0 30. 1,4-Di-(beta cyanoethoxy) butyne-Z (Com- 0.021.0 (average pound 2 of Table I). 0.2 g./1.).

Example Ill Oz./gal Grams/liter Copper cyanide-.- d 45. Sodium cyanide. 7. 5 56.2.5. Potassi 1m hydro 2. 5 18.75. Roch lle s*lts 4 30. l-hydmxyi-(beta cyanocthoxy) butyne-2 0.02-1.G (average (Compound 1 of Table I 0.1-0.3).

trodeposits over extended temperature ranges, and allows the operation of the electroplating baths over extended currentdensity ranges. The plating of irregular objects having projections and .recess es :is consequently t 3 greatly simplified. These improvements are obtained by using the baths of Examples V-VII which illustrate the brightest cyanide copper plating baths of this invention.

Example IV Grams/liter Copper cyanide 45 Sodium cyanide 56.5 Potassium hydroxide 18.75 Rochelle salts 30 Na or K salts of methylene bis-(alpha naphthalene sulfonic acid) (average 3 g./l.) 0.1-10.0

1-hydroxy-4-(beta cyanoethoxy) butyne-2 (compound 1 of Table I) 0.1-0.3

1 Daxad N0. 11 (Dewey and Almy Co.)

Example V Grams/liter Copper cyanide 45 Sodium cyanide 56.5 Potassium hydroxide 18.75 Rochelle salts 30 Tellurium (dissolved as TeO 0.00020.006 Na or K salt of methylene bis-(alpha naphthalene sulfonic acid 1 3 1,4-di-(betacyanoethoxy) butyne-2 (compound 2 The baths of Examples IV-VT produce uniformly bright very fine-grained ductile copper deposits over current densities extending from the highest to the lowest normally encountered in commercially important electroplating operations.

In generahwe'tting agents are not'needed especially with the less concentrated metal baths. Nevertheless, ,wetting agents may be employed, 'if desired. When cationic wetting agents are used, anionic wetting agents .such as sodium lauryl sulfate .or sodium dcdecyl ether sulfate should not be used unless the cationic. wetting agent is weakly cationic (short chain type). Non-ionic wetting agents may also be used.

Periodic current reversals or current interruption can be used with the above baths with some benefit. How- 'ever, because of the very wide bright plating range of Examples V-VI, the need for the use of'interrupted current or periodic current reversals is minimized. Sequestering or chelating agents, such as ethylene d' amine tetraacetates or similar compounds may be used in'the copper baths of this inventionto sequester impurities such as trivalent chromium, without affecting the brightness of the deposits.

What is claimed is:

' .1. A bath forelectrodepositing bright ductile copper comprising an aqueous alkaline copper cyanide solution containing dissolved therein an acetylenic ether nitrile selected from the group consisting of l-hydroxyA-(beta cyanoethoxy) butyne-Z and 1,4-di-(beta cyanoethoxy) :butyne-Z in an amount of from about 0.02 gram/liter to about 1.0 gram per liter.

2. A bath for'electrodepositing bright ductile copper "comprising an aqueous alkaline copper cyanide, solution to about 1.0 gramperliter'.

3. A bath for electrodepositing bright ductile copper comprising an aqueous alkaline copper cyanide solution containing the compound 1,4-di-(beta cyanoethoxy) butyne-2 dissolved therein in an amount from about 0.02 to about 10 gram per liter.

4. A bath for electrodepositing bright fine-grained ductile copper comprising an aqueous alkaline copper cyanide solution which contains about 0.1 to 10.0 grams perliter of a water soluble salt of methylene bis-(naphthalene sulfonic acids), and about 0.02 to about 1.0 gram per liter of at least one compound seletced from the group consisting of l-hydroxy-4-(beta cyanoethoxy) butyne-2,'.and 1,4-di-(beta cyanoethoxy) butyne-Z. v

5. A bath for electrodepositing bright fine-grained ductile copper comprising an aqueous alkaline copper cyanide solution which contains about 0.1 to 10.0 grams per liter of a water soluble salt of methylene bis-(naphthalene sulfonic acids), and about 0.02 to about 1.0 gram per liter of l-hydroxy-4-(beta cyanoethoxy) butyne-2.

6. A bath for electrodepositing bright fine-grained ductile copper comprising an aqueous alkaline copper cyanide solution which contains about 0.1 to 10.0 grams per liter of a water soluble salt of methylene bis-(naphthalene sulfonic acids), and about 0.02 to about 1.0 gram per liter of l,4-di-(beta cynaoethoxy) butyne-Z.

7. A bath for electrodepositing bright very fine-grained ductile copper comprising an aqueous alkaline copper cyanide solution containing an amount of tellurium dissolved therein in the range of about 0.0002 to about 0.006 gram per liter, about 0.1 to 10.0 grams/liter of a water soluble salt of methylene bis-(naphthalene sulfonic acids), and in addition thereto about 0.02 to about 1.0 gram per liter of at least one compound selected from the group consisting of l-hydroxy-4(beta cyanoethoxy) butyne-Z, and 1,4-di-(beta cyanoethoxy) butyne-Z.

8. A bath for electrodepositing bright fine-grained ductile copper comprising an aqueous alkaline copper cyanide solution containing about 0.1 to 10.0 grams per liter of a water soluble salt of methylene bis-(alpha naphthalene sulfonic acids), about 0.02 to about 1.0.gram per liter of at least one compound selected from the group consisting of 1-hydroxy-4-( beta cyanoethoxy) butyne-Z, and 1,4-di-(beta cyanoethoxy) butyne-2. V

9. A bath for electrodepositing bright very fine-grained ductile copper comprising an aqueous alkaline copper cyanide solution containing an amount .oftellurium dissolved therein in the range of about 0.0002 to about 0.006 gram per liter, about 0.1 to 10.0 grams per liter of a water soluble salt of methylene bis-( alpha naphthalene sulfonic acids), and in addition thereto about 0.02 to 1.0 grams per liter of at least one compound selected from the group '11. A method for electrodepositing bright ductile copper which comprises electrodepositing copper from an aqueous alkaline copper cyanide solution containing the compound l-hydroxyfl-(beta cyanoethoxy) butyne-Z disfsolved therein in an amount from about 0.02 to about 1.0 'gram per liter.

I 12. 'A method for'electrodepositing bright ductile copiper which :comprises electrodepositing copper; from an aqueous alkaline copper Cyanide solution containing' the compound 1,4-di(beta cyanoethoxy) butyne-Z dissolved V 13. A method for electrodepositing bright du'ctilefinegrained copper which comprises electrodepositing copper Ro fe from an aqueous alkaline copper cyanide solution containing about 0.1 to 10.0 grams per liter of a water soluble salt of methylene bis-naphthalene sulfonic acids), and about 0.02 to about 1.0 gram per liter of at least one compound selected from the group consisting of 1- hydroXy-4-(beta cyanoethoxy) butyne-Z, and 1,4-di-(beta cyanoethoxy) butyne-Z.

14. A method for electrodepositing bright ductile finegrained copper which comprises electrodepositing copper from an aqueous alkaline copper cyanide solution containing about 0.1 to 10.0 grams per liter of a water soluble salt of methylene bis-(naphthalene sulfonic acids), and about 0.02 to about 1.0 gram/liter of 1-hydroxy-4- (beta cyanoethoxy) butyne-Z.

15. A method for electrodepositing bright ductile finegrained copper which comprises electrodepositing copper from an aqueous alkaline copper cyanide solution containing about 0.1 to 10.0 grams per liter of a water solubie salt of methylene bis-(naphthalene sulfonic acids), and about 0.02 to about 1.0 gram per liter of 1,4-di-(beta cyanoethoxy) butyne-2.

16. A method for electrodepositing bright ductile very fine-grained copper which comprises electrodepositing copper from an aqueous alkaline copper cyanide solution containing an amount of tellurium dissolved therein in the range of about 0.0002 to about 0.006 gram/liter, about 0.1 to 10.0 grams/liter of a water soluble salt of methylene bis-(naphthalene sulfonic acids), and in addition thereto about 0.02 to about 1.0 gram per liter of at least one compound selected from the group con- 6 sisting of 1-hydroxy-4-(beta cyanoethoxy) butyne-2, and 1,4-di-(beta cyanoethoxy) butyne-Z.

17. A method for electrodepositing bright ductile finegrained copper which comprises electrodepositing copper from an aqueous alkaline copper cyanide solution containing about 0.1 to 10.0 grams per liter of a Water soluble salt of methylene bis(alpha naphthalene sulfonic acids), and in addition thereto about 0.02 to about 1.0 gram per liter of at least one compound selected from the group consisting of 1-hydroXy-4-(beta cyanoethoxy) butyne2, and 1,4-di-(beta cyanoethoxy) butyne-2.

18. A method for electrodepositing bright ductile very fine-grained copper which comprises electrodepositing copper from an aqueous alkaline copper cyanide solution containing an amount of tellurium dissoived therein in the range of about 0.0002 to about 0.006 gram/liter, about 0.1 to 10.0 grams per liter of a water soluble salt of methylene bis-(alpha naphthalene sulfonic acids), and in addition thereto about .02 to 1.0 gram per liter of at least one compound selected from the group consisting of l-hydroxy-4-(beta cyanoethoxy) butyne-Z, and 1,4-di-(beta cyanoethoxy) butyne-2.

References Cited in the file of this patent UNITED STATES PATENTS 2,841,542 Manquen July 1, 1958 2,881,122 Foulke et a1 Apr. 7, 1959 FOREIGN PATENTS 874,100 Germany Apr. 20, 1953 UNITED STATES PATENT OFFICE CETIFICATION OF CORRECTIUN Patent No 2 970351 February 7Y 1961 John W}, Manquen et ale It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column l extreme right hand portion. of the formula for Na or P etco q salts read Na or Kr, etc, 8 ealts ---g column 2 line 9 for "through" read though column 4 line 5 for '10 read 160 column. 5 line 3 for bis naynhizhalene sulfonic acids) read bis-(naphthalene sulfonic acids) Signed and sealed this 5th day of September 19616 (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

1. A BATH FOR ELECTRODEPOSITING BRITHT DUCTILE COPPER COMPRISING AN AQUEOUS ALKALINE COPPER CYANIDE SOLUTION CONTAINING DISSOLVED THEREIN AN ACETYLENIC ETHER NITRILE SELECTED FROM THE GROUP CONSISTING OF 1-HYDROXY-4-(BETA CYANOETHOXY) BUTENE-2 AND 1,4-DI-(BETA CYANOETHOXY) BUTYENE-2 IN AN AMOUNT OF FROM ABOUT 0.02 GRAM/LITER TO ABOUT 1.0 GRAM PER LITER. 